DegreesMinutesSeconds.java

/*******************************************************************************
 * Copyright (c) 2008, 2009 Bug Labs, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    - Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    - Neither the name of Bug Labs, Inc. nor the names of its contributors may be
 *      used to endorse or promote products derived from this software without
 *      specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *******************************************************************************/
package com.buglabs.nmea;

import com.buglabs.nmea.sentences.NMEAParserException;

/**
 * A class to store DMS style location information.
 * 
 * @author aroman
 * 
 */
public class DegreesMinutesSeconds {

	private String dms;
	private char direction = '?';

	/**
	 * Will throw NMEAParserException if parsing error occurs.
	 * 
	 * @param dms
	 */
	public DegreesMinutesSeconds(String dms) {
		if (dms == null || dms.length() == 0 || dms.indexOf(',') == -1 || dms.indexOf('.') == -1) {
			throw new NMEAParserException("Unable to parse DMS: " + dms);
		}

		int i = dms.indexOf(",");
		this.dms = dms.substring(0, i);

		if (dms.length() > i + 1) {
			direction = dms.charAt(i + 1);
		}
	}

	/**
	 * @return Degrees part of DMS
	 */
	public double getDegrees() {
		int i = dms.indexOf(".");

		if (i < 2) {
			throw new NMEAParserException("Unable to calculate degrees from " + dms);
		}

		double rawVal = Double.parseDouble(dms.substring(0, i - 2));

		// According to
		// http://www.nationalatlas.gov/articles/mapping/a_latlong.html
		// S and W directional designators offer negative values for degrees.
		if (direction == 'S' || direction == 'W') {
			rawVal = rawVal * -1;
		}

		return rawVal;
	}

	/**
	 * @return Minutes part of DMS value
	 */
	public double getMinutes() {
		int i = dms.indexOf(".");

		if (i < 2) {
			throw new NMEAParserException("Unable to calculate minutes from " + dms);
		}

		return Double.parseDouble(dms.substring(i - 2, i));
	}

	/**
	 * @return Seconds part of DMS value
	 */
	public double getSeconds() {
		int i = dms.indexOf(".");

		if (i == -1) {
			return 0;
		}

		String seconds = dms.substring(i);

		return Double.parseDouble(seconds) * 60;
	}

	/**
	 * @return Direction char for unit. Can be N/S/E/W.
	 */
	public char getDirection() {
		return direction;
	}

	/**
	 * Convert DegreesMinutesSeconds to decimal degrees
	 * 
	 * @return
	 */
	public double toDecimalDegrees() {
		double decimal = getSeconds() / 60.0;
		double result = (getMinutes() + decimal) / 60.0;

		double degrees = getDegrees();

		if (degrees < 0.0) {
			return degrees - result;
		}

		return degrees + result;
	}
}